The present invention is related to shoe insoles that modify the flexibility of a shoe sole.
Enthusiasts of certain sporting activities, such as bicycling, require special shoes that have stiff soles for transmitting downward forces past the tarsal and metatarsal bones of the feet to the bicycle pedals. The stiff soles transmit pedaling forces without requiring muscular effort by the wearer to maintain the feet in a horizontal orientation. Such soles therefore reduce leg and foot fatigue.
Stiff soled shoes, regardless of their intended purpose. are uncomfortable when walking. They resist plantar flexion in both upward and downward directions and therefore tend to cause the wearer to walk flat with an unnatural foot pattern.
The disclosed solution is a form of insole that can be adapted to standard forms of flexible soled shoes for allowing plantar flexion of the foot in one direction and inhibiting such flexion in an opposite direction beyond a normal, horizontal extended position of the foot.